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Stopping sewer overflows: What's being done to keep our fresh water clean

Posted at 9:19 PM, Sep 25, 2018
and last updated 2018-09-25 23:12:35-04

The rainy summer in Southeast Wisconsin overwhelmed the regional sewer system, leading to five sewer overflows in a four month span. 

That means nearly a billion gallons of untreated wastewater went into Lake Michigan and nearby rivers. But there is work being done to eventually get that number down to zero. 

It's something the executive director of the Milwaukee Metropolitan Sewerage District, Kevin Shafer, thinks about often. Every time it starts to rain, he begins to watch the forecast and radar closely. 

"I'm up all night when it rains," said Shafer. "Trying to keep an overflow from occurring." 

MMSD oversees flood management and wastewater for 28 municipalities in the region. 

Shafer says anytime one inch of rain falls over the area, that's 7 billion gallons of water that has to go somewhere. 

A lot of that water ends up in the deep tunnel system, an underground storage system for water. But that can only hold so much, about 521 million gallons. 

"When you get that much rainwater, it just fills up the tunnel really quick," said Shafer. 

That's why there's a large emphasis on green infrastructure, to try and reduce the amount of water that ends up in the deep tunnel system. 

Some of those options include using porous concrete to absorb water, installing green roofs on buildings and putting in bioswales along roadways that use specific vegetation to soak up water. 

MMSD has invested $4 billion to reduce sewer overflows and has a goal by 2035 to bring the number of overflows each year down to zero. 

"You can always try to do more," said Shafer. "If we wanted to spend a whole lot more money, we could build more storage or more conveyance. But what we’re really trying to do is get people to understand that when that drop of water falls from the sky and hits their property, there’s something they can do at their house." 

Individual residents can help by installing rain barrels and rain gardens to capture water and keep it from going into the sewer system. 

Between Aug. 20 and Sept. 6, MMSD dumped a combined 543 million gallons of untreated wastewater into rivers and Lake Michigan, during four separate overflows. 

That's in addition to seven individual municipalities in the region also had to conduct an overflow because their systems were overwhelmed during the same time frame. 

"It could be much worse," said Shafer. "That could be raw sewage in people's basement." 

Cheryl Nenn is part of the non-profit Milwaukee Riverkeeper, that advocates to improve water quality. She says as an organization, they are very concerned that MMSD has had five sewer overflows this year. 

"We worry about the impact on water quality, the impacts to people using the rivers and beaches and if their health could be impacted," said Nenn. 

MMSD hasn't had this many overflows since 2013. While each year's numbers depend on the amount of rainfall we receive, Nenn says we need to do more to prepare for extreme weather events. 

"How do we take all of this good work that's already happening and really ramp it up to the point that we need to become resilient to these extreme weather events," said Nenn.  

Before the deep tunnel was put into operation, the region had 50 to 60 overflows each year and up to nine billion gallons of untreated water polluted our local water ways. 

"We've come a long way but we still have a lot of work to do," said Nenn. 

To reach that goal of zero overflows a year, Shafer says every drop of water saved really does count. 

"It’s gonna be a lot of work," he said. "We’re going to have to do a lot of regional efforts and it’s much better when we all work together as opposed to little things being done." 

Shafer says MMSD reimburses for certain green infrastructure projects. You can find out more information about rain barrels, rain gardens and other green infrastructure initiatives here.